Method and apparatus of private display device

ABSTRACT

There is provided a system and method for providing privacy viewing of an output from a electronic display, including a first polarizer configured to polarize a display signal at a first polarization angle; a second polarizer configured to polarize a noise signal at a second polarization angle orthogonal to the first polarization angle; a combiner configured to combine the polarized display signal and the polarized noise signal, and a third polarizer configured to receive the output of the electronic display and polarize the combined polarized display and noise signal at the first polarization angle. The system includes first and second polarization rotators configured to rotate the first and second polarization angles of the combined polarized display and noise signals prior to being output by the electronic display and prior to being received by the third polarizer.

BACKGROUND OF THE INVENTION

This disclosure relates generally to viewing of an electronic display,and particularly to privacy viewing of an electronic display.

Nowadays, the display angle of electronic display screens has becomewider and wider and very close to 180°. This is good when people want towatch movies or share several screens together. However, in most cases,especially for personal computers, tablets and smart devices such assmart phones, people would like to have some privacy on the screen.

A privacy-filter manufactured by 3M® utilizes a micro-louver technology,in which only persons directly in front of the monitor can see the imageon screen. From the side, onlookers see only a darkened screen. The viewis narrowed, but not against the people behind the screen and it is noteasy to switch between the narrow view and the broad view.

In another prior art method, the viewing angle of the display iscontrolled, which is similar to the privacy filter but this still doesnot prevent the view behind the screen. Moreover, when the user changesposition, the angle of the display must be changed accordingly, whichmakes use inconvenient.

Virtual private theatre glasses are known. However, with theatreglasses, the user cannot see anything but the display inside of theglasses.

Therefore, what is needed is a convenient, totally private andenvironment aware device.

SUMMARY OF THE INVENTION

In one embodiment, there is provided a system for providing privacyviewing of an output from an electronic display. The system comprises afirst polarizer configured to polarize a display signal at a firstpolarization angle; a noise generator configured to supply a noisesignal; a second polarizer configured to polarize the noise signal at asecond polarization angle orthogonal to the first polarization angle; acombiner configured to combine the polarized display signal and thepolarized noise signal, the combined display and noise signal beingconfigured to be output by the electronic display; and a third polarizerconfigured to receive the output of the electronic display and polarizethe combined polarized display and noise signal at the firstpolarization angle.

In one embodiment, there is provided a system for providing privacyviewing of an output from an electronic display, which comprises; adisplay signal scrambler attached to an electronic display, the displaysignal scrambler comprising a first polarizer configured to polarize adisplay signal input to the display at a first polarization angle, anoise generator configured to supply a noise signal, a second polarizerconfigured to polarize the noise signal at a second polarization angleorthogonal to the first polarization angle, and a combiner configured tocombine the polarized display signal and the polarized noise signal, thecombined display and noise signal being configured to be output by theelectronic display; and a display signal descrambler comprising a thirdpolarizer configured to receive the output of the electronic display andpolarize the combined polarized display and noise signal at the firstpolarization angle.

In another embodiment, the system includes respective first and secondpolarization rotators configured to rotate the first and secondpolarization angles of the combined polarized display and noise signalsprior to being output by the electronic display and prior to beingreceived by the third polarizer, respectively.

In one embodiment, there is provided a method for providing privacyviewing of an output from a electronic display. The method comprises:polarizing a display signal received by the electronic display at afirst polarization angle; generating a noise signal; polarizing thenoise signal at a second polarization angle orthogonal to the firstpolarization angle; combining the polarized display signal and thepolarized noise signal; outputting the combined display and noise signalbeing from the electronic display; and receiving the output of theelectronic display and polarizing the combined polarized display andnoise signal at the first polarization angle.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, features and advantages of the presentinvention will become apparent from the following detailed descriptionof illustrative embodiments thereof, which is to be read in connectionwith the accompanying drawings, in which:

FIG. 1 is a schematic diagram of the system for providing privacyviewing of an output from a electronic display in one embodiment.

FIG. 2 is block diagram of the system for providing privacy viewing ofan output from a electronic display in one embodiment.

FIG. 3 is schematic depiction of the operation of a polarization rotatorused in of the system for providing privacy viewing of an output from aelectronic display in one embodiment.

FIG. 4 is flowchart of the method for scrambling the output signal of aelectronic display in one embodiment.

FIG. 5 is flowchart of the method for descrambling the output signal ofa electronic display in one embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In one embodiment, polarized light is used to enable a privacy display.The display applicable to this disclosure is any electronic display,including but not limited to a display for, a computer monitor, atelevision, tablet or smart phone, which outputs a display signal. Thedisplay signal may include but is not limited to any image that can beoutput from an electronic display, such a video and still images. Thedisplay signal is polarized in one direction. Noise polarized in theorthogonal direction is added to the polarized display signal making thecombined display unrecognizable. The polarization angle can be rotatedrandomly and only the authorized viewers can synchronize thepolarization and see the display clearly. The system can be set inmultiple working modes: Unique: Only one viewer can see the screen;Group: Only a group of viewers can see the screen; and Broadcast mode:everyone can see the screen. Since in nature light isn't polarized, theenvironment can be seen through the polarized glass as well.

As shown in FIG. 1, the privacy display system 10 includes displayscrambler 12 added in the screen side of a electronic display 14. Adisplay descrambler 16 is added in the viewer side of a viewing devicesuch as an eyeglass frame 18. The original image 20 is input to theelectronic display 14 and is scrambled by the scrambler 12. Thescrambled display signal that is output from the display 14 cannot beviewed by the naked eye. Only a user wearing the eyeglass frame 18 withthe descrambler 16 can view the descrambled image 24.

FIG. 2 shows the details of the scrambler 12 and the descrambler 16. Inthe scrambler 12, the original display signal 20 is polarized via apolarizer or polarization filter 26 with predefined angle è1. A whitenoise signal generator 28 generates a white noise signal that ispolarized via a linear polarizer or polarization filter 30 withpredefined angle è2. The polarization angles è1 and è2 are orthogonal toeach other. The embodiment shown in FIG. 2 shows the two angles as beingvertical and horizontal. However, this is just one example, as any twoangles may be used, as long as they are orthogonal to each other.

The polarized original signal and the orthogonally polarized noisesignal are combined in a signal processing combiner 32. As a result,after combining the polarized display and noise, the original displaysignal cannot be recognized by naked eyes, but can still be restored bythe polarized glasses with the polarization angel è1.

To further protect the sensitive display against unauthorized polarizedglasses users, a polarization rotator 34 is applied to the combinedsignal to constantly change the polarization angle based on a predefinedrotation pattern. In one embodiment a high speed random rotator is used,such as one sold by Lightwaves 2020 of Milipitas Calif. In oneembodiment, a thin, fast, low loss polarization rotator is used. Forexample, two mylar strips with thickness about 6.0 μm can be used as thecell gap spacers and then the cell is capillary filled with the liquidcrystal\ (E7,Merck-BDH)(LC=liquid crystal) as described in Fuzi Yang,Polarization Rotator Using a Hybrid Aligned Nematic Liquid Crystal Cell.Vol. 15, No. 7, Optics Express, Apr. 2, 2007. In one embodiment, theaccuracy and insertion loss is low by having the total device lengthkept short (less than 50 μm) and the insertion efficiency high at81%±19%, which corresponds to an insertion loss of 1 dB, as described inDaryl M. Beggs, 1, * Michele Midrio,2 and Thomas F. Krauss1, Compactpolarization rotators for integrated polarization diversity in InP-basedwaveguides, OPTICS LETTERS/Vol. 32, No. 15/2176/Aug. 1, 2007.

Alternatively, a random rotation pattern may be used. In one embodiment,the rotation pattern can be regarded as a key for encrypting displaysignal , and it may consist of dynamic rotation speed and the initialoffset of polarization angle. A rotation pattern generator 38 generatesthe rotation pattern applied to the polarization rotator 34.

The continuous rotation of the polarized angle prevents the displaysignal from being directly recognized by other users 39 with their nakedeye or using any polarized glasses with a fixed angle. A sync module 36passes the rotation pattern of rotation pattern generator 38 to thedescrambler 16 by sending a synchronization signal. Sync module 36 canbe in one emboidment an active shutter 3D system, which uses alternateframe sequencing, also known as alternate image, alternating field,field sequential or eclipse method, which is a technique of displayingstereoscopic 3D images. The method works by only presenting the imageintended for the left eye while blocking the right eye's view, thenpresenting the right-eye image while blocking the left eye, andrepeating this so rapidly that the interruptions do not interfere withthe perceived fusion of the two images into a single 3D image. Thismethod for the sync module 36 is described in Active Shutter 3DTechnology for HDTV″, PhysOrg, Sep. 25, 2009. However, any kind of syncmechanism can be used for sync module 36 provided it can make sure therandom rotation pattern can be correctly and immediately transmittedfrom the display to glass.

FIG. 3 schematically depicts the operation of a polarization rotator.The polarization rotator operates by the Faraday Effect. ThePolarization rotator can rotate the polarization axis of a linearlypolarized light signal. The angle of rotation of the polarization isdecided by B, d and v, shown in FIG. 3. B is the magnetic flux densityin the direction of propagation (in teslas). d is the length of the path(in meters) where the light and magnetic fields interact. v is theVerdet constant for the material. This empirical proportionalityconstant (in units of radians per tesla per meter) varies withwavelength and temperature and is tabulated for various materials. B canbe controlled electrically by voltage. As noted above, polarizationrotators can be very thin, such as the liquid crystal cell of 6umdisclosed in Fuzi Yang, Polarization Rotator Using a Hybrid AlignedNematic Liquid Crystal Cell. Vol. 15, No. 7, Optics Express, Apr. 2,2007.

Referring again to FIG. 2, in the descrambler 16, a sync module 40 willsynchronize with scrambler sync module 36 to cause rotation patterngenerator 41 to apply the same scrambler rotation pattern topolarization rotator 42. Polarization rotator 42 anti-rotates thescrambled display signal 44, using the same angle and pace of thescrambler polarization rotator 34. Thereafter, by passing anti-rotatedsignal through polarizer/polarization filter 46 having the samepolarization angle of filter 26 of the scrambler 12, the display signal48 is restored for privacy viewing by the wearer of the descrambler 16.

In the synchronization mode, the scrambler 12 and descrambler 16 canhave an authorization technology to make sure the rotation patterncannot be easily detected by unauthorized users. For example, thescramble pattern generator can use a user's PIN or other securitytechnologies to create a unique scramble pattern for each user. Separatesynchronization technologies can be used, in one embodiment, for thescrambler 12 and the descramble 16. In addition, the synchronizationsignal can be sent wired or wireless. For example: scrambler 12 sends awireless synchronization preamble and descrambler 16 syncs to that orboth sync to some external reference like Wi-Fi AP. Through theauthorization process, unique private view and group based private viewcan be supported.

FIG. 4 is a flow chart depicting the method of generating a scrambleddisplay output. In step S1, whether scramble is enabled is determined.If NO then the original unscrambled display signal is output. If YES,then the display signal is polarized in step S2 using first polarizationfilter, shown as horizontal is this embodiment. In step S3, white noiseis generated and in step S4 the white noise is polarized using avertical polarization filter. In step S5, the polarized original signaland orthogonally polarized white noise signal are combined. In step S6 async signal is generated and sent to a rotation pattern generator. Thesync signal is also sent for receipt by the descrambler in step S6. Instep S7, a rotation pattern is generated based on the sync signal. Instep S8, the polarization of the combined original and noise signal isrotated according to the rotation pattern and the scrambled signal isoutput.

FIG. 5 is a flow chart that depicts the method of descrambling thescrambled electronic display signal. In step S9, the sync signal fromthe scrambler is received by the descrambler. In step S10 theanti-rotation pattern is generated. In step S11 the scrambled displaysignal is received and the polarization is rotated according to theanti-rotation pattern. In step S12 the ant-rotated signal is polarizedusing the horizontal polarization filter and the descrambled electronicdisplay signal is output for viewing only by the wearer of thedescrambler.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

Computer readable program instructions may be provided to a processor ofa general purpose computer, special purpose computer, or otherprogrammable data processing apparatus to produce a machine, such thatthe instructions, which execute via the processor of the computer orother programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The flowcharts, block diagrams and schematics in the Figures illustratethe architecture, functionality, and operation of possibleimplementations of systems, methods and computer program productsaccording to various embodiments of the present invention. In thisregard, each block in the flowcharts, schematics or block diagrams mayrepresent a module, segment, or portion of instructions, which comprisesone or more executable instructions for implementing the specifiedlogical function(s). In some alternative implementations, the functionsnoted in the block may occur out of the order noted in the figures. Forexample, two blocks shown in succession may, in fact, be executedsubstantially concurrently, or the blocks may sometimes be executed inthe reverse order, depending upon the functionality involved. It willalso be noted that each block of the block diagrams and/or flowchartillustration, and combinations of blocks in the block diagrams and/orflowchart illustration, can be implemented by special purposehardware-based systems that perform the specified functions or acts orcarry out combinations of special purpose hardware and computerinstructions.

While the invention has been particularly shown and described withrespect to illustrative and preformed embodiments thereof, it will beunderstood by those skilled in the art that the foregoing and otherchanges in form and details may be made therein without departing fromthe spirit and scope of the invention which should be limited only bythe scope of the appended claims.

What is claimed is:
 1. A system for providing privacy viewing of anoutput from an electronic display, the system comprising: a firstpolarizer configured to polarize a display signal at a firstpolarization angle; a noise generator configured to supply a noisesignal; a second polarizer configured to polarize the noise signal at asecond polarization angle orthogonal to the first polarization angle; acombiner configured to combine the polarized display signal and thepolarized noise signal, the combined display and noise signal beingconfigured to be output by the electronic display; a first polarizationrotator configured to continuously rotate the first and secondpolarization angles of the combined polarized display and noise signalsprior to being output by the electronic display; a second polarizationrotator configured to continuously anti-rotate the first and secondpolarization angles of the combined polarized display and noise signalsprior to being received by the third polarizer; first and secondrotation pattern generators for providing first and second a rotationpatterns to the first and second polarization rotators, respectively;first and second synchronization modules for synchronizing the first andsecond rotation patterns provided to each other; and a third polarizerconfigured to receive the output of the electronic display and polarizethe combined polarized display and noise signal at the firstpolarization angle.
 2. The system according to claim 1, wherein thefirst and second rotation pattern generators provide a predefined orrandom rotation pattern to the first and second polarization rotators.3. The system according to claim 1, wherein the respective rotationpattern generators require a unique user authorization code to generatea corresponding unique predefined rotation pattern.
 4. The systemaccording to claim 1, wherein the rotation pattern comprises anencryption key including a dynamic rotation speed of the firstpolarization rotator and an initial offset of the first polarizationangle.
 5. The system according to claim 1, wherein the first and secondpolarization rotators operate according to the Faraday Effect.
 6. Thesystem according to claim 1, wherein the first and secondsynchronization modules synchronize the rotation angle of the rotationpatterns.
 7. The system according to claim 1, wherein the first andsecond synchronization modules synchronize the pace of rotation of therotation patterns.
 8. The system according to claim 1, wherein the firstand second synchronization modules each comprise a 3D shutter system fordisplaying stereoscopic 3D images.
 9. A system for providing privacyviewing of an output from an electronic display, the system comprising:a display signal scrambler attached to a electronic display, the displaysignal scrambler comprising a first polarizer configured to polarize adisplay signal input to the display at a first polarization angle, anoise generator configured to supply a noise signal, a second polarizerconfigured to polarize the noise signal at a second polarization angleorthogonal to the first polarization angle, a combiner configured tocombine the polarized display signal and the polarized noise signal, afirst polarization rotator configured to continuously rotate the firstand second polarization angles of the combined polarized display andnoise signals, a first rotation pattern generator for providing a firstrotation pattern to the first polarization rotator, and a firstsynchronization module for synchronizing the first rotation patternprovided to the first polarization rotator, the combined and rotateddisplay and noise signal being configured to be output by the electronicdisplay; and a display signal descrambler comprising a secondpolarization rotator configured to receive the output of the electronicdisplay and continuously anti-rotate the first and second polarizationangles of the combined and rotated polarized display and noise signals,a second rotation pattern generator for providing a second rotationpattern to the second polarization rotator, a second synchronizationmodule for synchronizing the second rotation pattern provided to thesecond polarization rotator, and a third polarizer configured topolarize the combined and rotated polarized display and noise signal atthe first polarization angle, wherein the first and secondsynchronization modules synchronize the first and second rotationpatterns to each other.
 10. The system according to claim 9, wherein thefirst and second rotation pattern generators provide respectivepredefined or random rotation patterns to the first and secondpolarization rotators.
 11. The system according to claim 9, wherein thefirst and second rotation pattern generators require a unique userauthorization code to generate a corresponding unique predefinedrotation pattern and the first and second rotation patterns comprises anencryption key including a dynamic rotation speed of the firstpolarization rotator and an initial offset of the first polarizationangle.
 12. The system according to claim 9, wherein the first and secondpolarization rotators operate according to the Faraday Effect.
 13. Thesystem according to claim 9, wherein the first and secondsynchronization modules synchronize the rotation angle of the rotationpatterns.
 14. The system according to claim 9, wherein the first andsecond synchronization modules synchronize the pace of rotation of therotation patterns.
 15. The system according to claim 9, wherein thefirst and second synchronization modules each comprise a 3D shuttersystem for displaying stereoscopic 3D images.
 16. A method for providingprivacy viewing of an output from an electronic display, the methodcomprising: polarizing a display signal input to the display at a firstpolarization angle, supplying a noise signal, polarizing the noisesignal at a second polarization angle orthogonal to the firstpolarization angle, combining the polarized display signal and thepolarized noise signal, continuously rotating the first and secondpolarization angles of the combined polarized display and noise signals,providing a first rotation pattern to a first polarization rotator,synchronizing the first rotation pattern provided to the firstpolarization rotator, outputting the combined and rotated display andnoise signal to the electronic display; receiving the output of theelectronic display, continuously anti-rotating the first and secondpolarization angles of the combined and rotated polarized display andnoise signals, providing a second rotation pattern to a secondpolarization rotator, synchronizing the second rotation pattern providedto the second polarization rotator, and polarizing the combined androtated polarized display and noise signal at the first polarizationangle, wherein the first and second rotation patterns are synchronizedto each other.
 17. The method according to claim 16, further includingproviding a predefined or random rotation pattern to the first andsecond polarization rotators.
 18. The method according to claim 16,further including requiring a unique user authorization code to generatea corresponding unique predefined rotation pattern and providing anencryption key including a dynamic rotation speed of the first rotationpolarizer and an initial offset of the first polarization angle.
 19. Themethod according to claim 16, wherein the synchronizing includessynchronizing the rotation angle and the pace of rotation of the firstand second rotation patterns.
 20. The method according to claim 16,further including displaying stereoscopic 3D images. using a 3D shuttersystem.